Graphical calculi enable reasoning about quantum computation in an intuitive yet rigorous way.
Calculi based on string diagrams are more flexible than circuit-style languages, allowing the description of states and measurement projections as well as unitary operations in one unified framework.
Their rigour is ensured by the category-theoretical underpinnings [1]}.
The best-known of these graphical languages is the ZX-calculus, which was first introduced 10 years ago [2]}, [3]}.
It is built around the interactions of two complementary bases, the computational basis and the Hadamard basis, which are graphically represented by so-called spiders.
A related formalism is the ZW-calculus [4]}, which is built around the interactions of generators related to the two different types of three-qubit entangled states: GHZ states and \(W\)  states.
